After shakedown, Grant County performed amphibious exercises.along
the Atlantic coast and in the Caribbean throughout 1958. From 1958 to 1962
the LST excelled in training and experimental amphibious operations in the
Atlantic, Caribbean, and on two occasions the Mediterranean (1958, 1961)
.

Following operations with Marines at Camp Pendleton in October 1962, Grant
County was dispatched to Florida for assignment during the Cuban missile
crisis. Her constant training paid dividends, for the show of strength displayed
by the Navy averted an atomic catastrophe, and once again left undisputed
America's claim to superiority of the sea. When the crisis eased, Grant
County resumed her training, and remained on alert in the event of another
flare-up.

In May 1965, the Communist threat to the Western Hemisphere struck again,
this time in the Dominican Republic. President Johnson ordered Marines to
the Caribbean island to protect American interests and help stabilize the
government. When the situation showed signs of diminishing, Grant County
departed Little Creek, Va., 1 June for the Caribbean. She embarked Marines
and Seabees stationed in the Dominican Republic and returned them to the
United States. On 3 October she sailed for another Mediterranean deployment
and participated in amphibious exercises before returning home 31 March
1966.

During the next 4 months Grant County participated in intermittent
amphibious exercises along the Atlantic Coast and in the Caribbean. During
August she made two runs to the Dominican Republic to return troops and
equipment to the United States. She continued shuttle runs along the East
Coast until 1 December when she began a 3-month overhaul. In March 1967
she resumed training and readiness operations with amphibious forces and
at present she ranges the seas from the Virginia Capes to the Caribbean
while maintaining the efficiency and readiness of her crew and equipment.